Evaluation of Warm Mix Asphalt Technology in Flexible Pavements

Warm mix asphalt (WMA) describes various technologies that allow asphalt mixtures to be produced at lower temperatures as compared to hot mix asphalt (HMA). WMA technologies also offer improvements in workability, cost, and environmental sustainability such as reduced fuel usage, greenhouse gas emissions, and wear and tear at plants, while enhancing worker health and safety conditions. The primary objective of this study was to evaluate the laboratory performance of plant-produced lab-compacted mixtures utilizing various WMA technologies, including some mixtures with higher percentages of RAP. The secondary objective of this study was to compare WMA energy consumption cost and emission data to conventional HMA mixtures in terms of fuel/energy savings at the plant and in terms of CO and CO2 emissions. Six projects in Louisiana utilizing four different WMA technologies were considered in this study, yielding 20 mixtures total. Each project included a companion HMA mixture section to allow for direct comparison. Loose mixtures were obtained from trucks at the plant and compacted on-site in a mobile asphalt laboratory. Laboratory tests included dynamic modulus (|E*|), flow number (FN), loaded wheel tracking (LWT) test, indirect tensile (IDT) test, semi-circular bend (SCB) test, thermal stress restrained specimen test (TSRST), and the Lottman moisture susceptibility test. Results indicated that WMA mixtures exhibit similar high and intermediate temperature performances in the laboratory as compared to HMA. On average, $1.61 of energy savings per ton of produced asphalt mixture was observed, along with a considerable reduction in air pollutants at the plant. However, the cost of additives and royalty fees would reduce the total cost savings from using WMA. These benefits were observed without reduction in the mechanistic performance of the mix.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 200p

Subject/Index Terms

Filing Info

  • Accession Number: 01675711
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA.15/553
  • Files: TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Jul 17 2018 3:46PM